Which topical medication has no correlation with diagnosing Horner's Syndrome?

Topical medications play varying roles in the evaluation and diagnosis of Horner's Syndrome, a condition resulting from disruption of sympathetic pathways that affects the eye and surrounding structures. Cocaine is used in clinical practice as it can help to differentiate between preganglionic and postganglionic lesions associated with Horner's Syndrome. Apraclonidine, an alpha-2 adrenergic agonist, is similarly used, as it can help to identify the presence of Horner's by inducing a noticeable increase in pupil size on the affected side due to denervation hypersensitivity.

Phenylephrine, a potent alpha-1 agonist, is also employed in the assessment of Horner's Syndrome, particularly in its ability to dilate pupils and help determine sympathetic function.

In contrast, tropicamide, primarily a muscarinic antagonist used for pupil dilation and cycloplegia in routine examinations, does not provide diagnostic information relevant to Horner's Syndrome. Its effect on the pupil is unrelated to the sympathetic pathways involved in Horner’s and does not contribute to the diagnostic process for this syndrome. Therefore, it can be concluded that tropicamide has no correlation with diagnosing Horner's Syndrome, making it the correct answer.